mirror of
https://github.com/nushell/nushell.git
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8e2917b9ae
# Description This makes assignment operations and `const` behave the same way `let` and `mut` do, absorbing the rest of the pipeline. Changes the lexer to be able to recognize assignment operators as a separate token, and then makes the lite parser continue to push spans into the same command regardless of any redirections or pipes if an assignment operator is encountered. Because the pipeline is no longer split up by the lite parser at this point, it's trivial to just parse the right hand side as if it were a subexpression not contained within parentheses. # User-Facing Changes Big breaking change. These are all now possible: ```nushell const path = 'a' | path join 'b' mut x = 2 $x = random int $x = [1 2 3] | math sum $env.FOO = random chars ``` In the past, these would have led to (an attempt at) bare word string parsing. So while `$env.FOO = bar` would have previously set the environment variable `FOO` to the string `"bar"`, it now tries to run the command named `bar`, hence the major breaking change. However, this is desirable because it is very consistent - if you see the `=`, you can just assume it absorbs everything else to the right of it. # Tests + Formatting Added tests for the new behaviour. Adjusted some existing tests that depended on the right hand side of assignments being parsed as barewords. # After Submitting - [ ] release notes (breaking change!)
641 lines
22 KiB
Rust
641 lines
22 KiB
Rust
use nu_protocol::{ParseError, Span};
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#[derive(Debug, PartialEq, Eq, Clone, Copy)]
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pub enum TokenContents {
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Item,
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Comment,
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Pipe,
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PipePipe,
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AssignmentOperator,
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ErrGreaterPipe,
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OutErrGreaterPipe,
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Semicolon,
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OutGreaterThan,
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OutGreaterGreaterThan,
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ErrGreaterThan,
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ErrGreaterGreaterThan,
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OutErrGreaterThan,
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OutErrGreaterGreaterThan,
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Eol,
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}
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#[derive(Debug, PartialEq, Eq)]
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pub struct Token {
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pub contents: TokenContents,
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pub span: Span,
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}
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impl Token {
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pub fn new(contents: TokenContents, span: Span) -> Token {
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Token { contents, span }
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}
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}
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#[derive(Clone, Copy, Debug)]
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pub enum BlockKind {
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Paren,
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CurlyBracket,
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SquareBracket,
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AngleBracket,
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}
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impl BlockKind {
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fn closing(self) -> u8 {
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match self {
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BlockKind::Paren => b')',
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BlockKind::SquareBracket => b']',
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BlockKind::CurlyBracket => b'}',
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BlockKind::AngleBracket => b'>',
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}
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}
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}
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// A baseline token is terminated if it's not nested inside of a paired
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// delimiter and the next character is one of: `|`, `;`, `#` or any
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// whitespace.
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fn is_item_terminator(
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block_level: &[BlockKind],
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c: u8,
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additional_whitespace: &[u8],
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special_tokens: &[u8],
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) -> bool {
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block_level.is_empty()
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&& (c == b' '
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|| c == b'\t'
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|| c == b'\n'
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|| c == b'\r'
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|| c == b'|'
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|| c == b';'
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|| additional_whitespace.contains(&c)
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|| special_tokens.contains(&c))
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}
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/// Assignment operators have special handling distinct from math expressions, as they cause the
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/// rest of the pipeline to be consumed.
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pub fn is_assignment_operator(bytes: &[u8]) -> bool {
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matches!(bytes, b"=" | b"+=" | b"++=" | b"-=" | b"*=" | b"/=")
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}
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// A special token is one that is a byte that stands alone as its own token. For example
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// when parsing a signature you may want to have `:` be able to separate tokens and also
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// to be handled as its own token to notify you you're about to parse a type in the example
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// `foo:bar`
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fn is_special_item(block_level: &[BlockKind], c: u8, special_tokens: &[u8]) -> bool {
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block_level.is_empty() && special_tokens.contains(&c)
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}
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pub fn lex_item(
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input: &[u8],
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curr_offset: &mut usize,
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span_offset: usize,
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additional_whitespace: &[u8],
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special_tokens: &[u8],
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in_signature: bool,
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) -> (Token, Option<ParseError>) {
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// This variable tracks the starting character of a string literal, so that
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// we remain inside the string literal lexer mode until we encounter the
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// closing quote.
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let mut quote_start: Option<u8> = None;
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let mut in_comment = false;
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let token_start = *curr_offset;
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// This Vec tracks paired delimiters
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let mut block_level: Vec<BlockKind> = vec![];
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// The process of slurping up a baseline token repeats:
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//
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// - String literal, which begins with `'` or `"`, and continues until
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// the same character is encountered again.
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// - Delimiter pair, which begins with `[`, `(`, or `{`, and continues until
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// the matching closing delimiter is found, skipping comments and string
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// literals.
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// - When not nested inside of a delimiter pair, when a terminating
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// character (whitespace, `|`, `;` or `#`) is encountered, the baseline
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// token is done.
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// - Otherwise, accumulate the character into the current baseline token.
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while let Some(c) = input.get(*curr_offset) {
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let c = *c;
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if let Some(start) = quote_start {
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// Check if we're in an escape sequence
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if c == b'\\' && start == b'"' {
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// Go ahead and consume the escape character if possible
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if input.get(*curr_offset + 1).is_some() {
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// Successfully escaped the character
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*curr_offset += 2;
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continue;
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} else {
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let span = Span::new(span_offset + token_start, span_offset + *curr_offset);
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return (
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Token {
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contents: TokenContents::Item,
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span,
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},
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Some(ParseError::UnexpectedEof(
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(start as char).to_string(),
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Span::new(span.end - 1, span.end),
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)),
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);
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}
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}
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// If we encountered the closing quote character for the current
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// string, we're done with the current string.
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if c == start {
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// Also need to check to make sure we aren't escaped
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quote_start = None;
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}
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} else if c == b'#' {
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if is_item_terminator(&block_level, c, additional_whitespace, special_tokens) {
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break;
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}
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in_comment = true;
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} else if c == b'\n' || c == b'\r' {
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in_comment = false;
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if is_item_terminator(&block_level, c, additional_whitespace, special_tokens) {
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break;
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}
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} else if in_comment {
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if is_item_terminator(&block_level, c, additional_whitespace, special_tokens) {
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break;
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}
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} else if is_special_item(&block_level, c, special_tokens) && token_start == *curr_offset {
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*curr_offset += 1;
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break;
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} else if c == b'\'' || c == b'"' || c == b'`' {
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// We encountered the opening quote of a string literal.
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quote_start = Some(c);
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} else if c == b'[' {
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// We encountered an opening `[` delimiter.
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block_level.push(BlockKind::SquareBracket);
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} else if c == b'<' && in_signature {
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block_level.push(BlockKind::AngleBracket);
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} else if c == b'>' && in_signature {
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if let Some(BlockKind::AngleBracket) = block_level.last() {
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let _ = block_level.pop();
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}
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} else if c == b']' {
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// We encountered a closing `]` delimiter. Pop off the opening `[`
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// delimiter.
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if let Some(BlockKind::SquareBracket) = block_level.last() {
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let _ = block_level.pop();
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}
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} else if c == b'{' {
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// We encountered an opening `{` delimiter.
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block_level.push(BlockKind::CurlyBracket);
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} else if c == b'}' {
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// We encountered a closing `}` delimiter. Pop off the opening `{`.
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if let Some(BlockKind::CurlyBracket) = block_level.last() {
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let _ = block_level.pop();
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} else {
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// We encountered a closing `}` delimiter, but the last opening
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// delimiter was not a `{`. This is an error.
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let span = Span::new(span_offset + token_start, span_offset + *curr_offset);
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*curr_offset += 1;
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return (
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Token {
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contents: TokenContents::Item,
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span,
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},
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Some(ParseError::Unbalanced(
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"{".to_string(),
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"}".to_string(),
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Span::new(span.end, span.end + 1),
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)),
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);
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}
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} else if c == b'(' {
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// We encountered an opening `(` delimiter.
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block_level.push(BlockKind::Paren);
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} else if c == b')' {
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// We encountered a closing `)` delimiter. Pop off the opening `(`.
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if let Some(BlockKind::Paren) = block_level.last() {
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let _ = block_level.pop();
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} else {
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// We encountered a closing `)` delimiter, but the last opening
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// delimiter was not a `(`. This is an error.
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let span = Span::new(span_offset + token_start, span_offset + *curr_offset);
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*curr_offset += 1;
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return (
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Token {
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contents: TokenContents::Item,
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span,
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},
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Some(ParseError::Unbalanced(
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"(".to_string(),
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")".to_string(),
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Span::new(span.end, span.end + 1),
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)),
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);
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}
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} else if c == b'r' && input.get(*curr_offset + 1) == Some(b'#').as_ref() {
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// already checked `r#` pattern, so it's a raw string.
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let lex_result = lex_raw_string(input, curr_offset, span_offset);
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let span = Span::new(span_offset + token_start, span_offset + *curr_offset);
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if let Err(e) = lex_result {
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return (
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Token {
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contents: TokenContents::Item,
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span,
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},
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Some(e),
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);
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}
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} else if c == b'|' && is_redirection(&input[token_start..*curr_offset]) {
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// matches err>| etc.
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*curr_offset += 1;
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break;
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} else if is_item_terminator(&block_level, c, additional_whitespace, special_tokens) {
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break;
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}
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*curr_offset += 1;
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}
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let span = Span::new(span_offset + token_start, span_offset + *curr_offset);
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if let Some(delim) = quote_start {
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// The non-lite parse trims quotes on both sides, so we add the expected quote so that
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// anyone wanting to consume this partial parse (e.g., completions) will be able to get
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// correct information from the non-lite parse.
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return (
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Token {
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contents: TokenContents::Item,
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span,
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},
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Some(ParseError::UnexpectedEof(
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(delim as char).to_string(),
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Span::new(span.end - 1, span.end),
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)),
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);
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}
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// If there is still unclosed opening delimiters, remember they were missing
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if let Some(block) = block_level.last() {
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let delim = block.closing();
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let cause = ParseError::UnexpectedEof(
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(delim as char).to_string(),
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Span::new(span.end - 1, span.end),
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);
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return (
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Token {
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contents: TokenContents::Item,
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span,
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},
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Some(cause),
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);
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}
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// If we didn't accumulate any characters, it's an unexpected error.
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if *curr_offset - token_start == 0 {
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return (
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Token {
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contents: TokenContents::Item,
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span,
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},
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Some(ParseError::UnexpectedEof("command".to_string(), span)),
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);
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}
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let mut err = None;
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let output = match &input[(span.start - span_offset)..(span.end - span_offset)] {
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bytes if is_assignment_operator(bytes) => Token {
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contents: TokenContents::AssignmentOperator,
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span,
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},
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b"out>" | b"o>" => Token {
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contents: TokenContents::OutGreaterThan,
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span,
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},
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b"out>>" | b"o>>" => Token {
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contents: TokenContents::OutGreaterGreaterThan,
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span,
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},
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b"out>|" | b"o>|" => {
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err = Some(ParseError::Expected(
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"`|`. Redirecting stdout to a pipe is the same as normal piping.",
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span,
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));
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Token {
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contents: TokenContents::Item,
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span,
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}
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}
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b"err>" | b"e>" => Token {
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contents: TokenContents::ErrGreaterThan,
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span,
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},
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b"err>>" | b"e>>" => Token {
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contents: TokenContents::ErrGreaterGreaterThan,
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span,
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},
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b"err>|" | b"e>|" => Token {
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contents: TokenContents::ErrGreaterPipe,
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span,
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},
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b"out+err>" | b"err+out>" | b"o+e>" | b"e+o>" => Token {
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contents: TokenContents::OutErrGreaterThan,
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span,
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},
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b"out+err>>" | b"err+out>>" | b"o+e>>" | b"e+o>>" => Token {
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contents: TokenContents::OutErrGreaterGreaterThan,
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span,
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},
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b"out+err>|" | b"err+out>|" | b"o+e>|" | b"e+o>|" => Token {
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contents: TokenContents::OutErrGreaterPipe,
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span,
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},
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b"&&" => {
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err = Some(ParseError::ShellAndAnd(span));
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Token {
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contents: TokenContents::Item,
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span,
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}
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}
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b"2>" => {
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err = Some(ParseError::ShellErrRedirect(span));
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Token {
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contents: TokenContents::Item,
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span,
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}
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}
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b"2>&1" => {
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err = Some(ParseError::ShellOutErrRedirect(span));
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Token {
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contents: TokenContents::Item,
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span,
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}
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}
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_ => Token {
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contents: TokenContents::Item,
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span,
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},
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};
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(output, err)
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}
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fn lex_raw_string(
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input: &[u8],
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curr_offset: &mut usize,
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span_offset: usize,
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) -> Result<(), ParseError> {
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// A raw string literal looks like `echo r#'Look, I can use 'single quotes'!'#`
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// If the next character is `#` we're probably looking at a raw string literal
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// so we need to read all the text until we find a closing `#`. This raw string
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// can contain any character, including newlines and double quotes without needing
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// to escape them.
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//
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// A raw string can contain many `#` as prefix,
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// incase if there is a `'#` or `#'` in the string itself.
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// E.g: r##'I can use '#' in a raw string'##
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let mut prefix_sharp_cnt = 0;
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let start = *curr_offset;
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while let Some(b'#') = input.get(start + prefix_sharp_cnt + 1) {
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prefix_sharp_cnt += 1;
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}
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// curr_offset is the character `r`, we need to move forward and skip all `#`
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// characters.
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//
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// e.g: r###'<body>
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// ^
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// ^
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// curr_offset
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*curr_offset += prefix_sharp_cnt + 1;
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// the next one should be a single quote.
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if input.get(*curr_offset) != Some(&b'\'') {
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return Err(ParseError::Expected(
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"'",
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Span::new(span_offset + *curr_offset, span_offset + *curr_offset + 1),
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));
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}
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*curr_offset += 1;
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let mut matches = false;
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while let Some(ch) = input.get(*curr_offset) {
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// check for postfix '###
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if *ch == b'#' {
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let start_ch = input[*curr_offset - prefix_sharp_cnt];
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let postfix = &input[*curr_offset - prefix_sharp_cnt + 1..=*curr_offset];
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if start_ch == b'\'' && postfix.iter().all(|x| *x == b'#') {
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matches = true;
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break;
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}
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}
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*curr_offset += 1
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}
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if !matches {
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let mut expected = '\''.to_string();
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expected.push_str(&"#".repeat(prefix_sharp_cnt));
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return Err(ParseError::UnexpectedEof(
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expected,
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Span::new(span_offset + *curr_offset - 1, span_offset + *curr_offset),
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));
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}
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Ok(())
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}
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pub fn lex_signature(
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input: &[u8],
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span_offset: usize,
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additional_whitespace: &[u8],
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special_tokens: &[u8],
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skip_comment: bool,
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) -> (Vec<Token>, Option<ParseError>) {
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lex_internal(
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input,
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span_offset,
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additional_whitespace,
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special_tokens,
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skip_comment,
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true,
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)
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}
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pub fn lex(
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input: &[u8],
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span_offset: usize,
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additional_whitespace: &[u8],
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special_tokens: &[u8],
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skip_comment: bool,
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) -> (Vec<Token>, Option<ParseError>) {
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lex_internal(
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input,
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span_offset,
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additional_whitespace,
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special_tokens,
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skip_comment,
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false,
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)
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}
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fn lex_internal(
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input: &[u8],
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span_offset: usize,
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additional_whitespace: &[u8],
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special_tokens: &[u8],
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skip_comment: bool,
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// within signatures we want to treat `<` and `>` specially
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in_signature: bool,
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) -> (Vec<Token>, Option<ParseError>) {
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let mut error = None;
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let mut curr_offset = 0;
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let mut output = vec![];
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let mut is_complete = true;
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while let Some(c) = input.get(curr_offset) {
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let c = *c;
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if c == b'|' {
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// If the next character is `|`, it's either `|` or `||`.
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let idx = curr_offset;
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let prev_idx = idx;
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curr_offset += 1;
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// If the next character is `|`, we're looking at a `||`.
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if let Some(c) = input.get(curr_offset) {
|
|
if *c == b'|' {
|
|
let idx = curr_offset;
|
|
curr_offset += 1;
|
|
output.push(Token::new(
|
|
TokenContents::PipePipe,
|
|
Span::new(span_offset + prev_idx, span_offset + idx + 1),
|
|
));
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Otherwise, it's just a regular `|` token.
|
|
|
|
// Before we push, check to see if the previous character was a newline.
|
|
// If so, then this is a continuation of the previous line
|
|
if let Some(prev) = output.last_mut() {
|
|
match prev.contents {
|
|
TokenContents::Eol => {
|
|
*prev = Token::new(
|
|
TokenContents::Pipe,
|
|
Span::new(span_offset + idx, span_offset + idx + 1),
|
|
);
|
|
// And this is a continuation of the previous line if previous line is a
|
|
// comment line (combined with EOL + Comment)
|
|
//
|
|
// Initially, the last one token is TokenContents::Pipe, we don't need to
|
|
// check it, so the beginning offset is 2.
|
|
let mut offset = 2;
|
|
while output.len() > offset {
|
|
let index = output.len() - offset;
|
|
if output[index].contents == TokenContents::Comment
|
|
&& output[index - 1].contents == TokenContents::Eol
|
|
{
|
|
output.remove(index - 1);
|
|
offset += 1;
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
_ => {
|
|
output.push(Token::new(
|
|
TokenContents::Pipe,
|
|
Span::new(span_offset + idx, span_offset + idx + 1),
|
|
));
|
|
}
|
|
}
|
|
} else {
|
|
output.push(Token::new(
|
|
TokenContents::Pipe,
|
|
Span::new(span_offset + idx, span_offset + idx + 1),
|
|
));
|
|
}
|
|
|
|
is_complete = false;
|
|
} else if c == b';' {
|
|
// If the next character is a `;`, we're looking at a semicolon token.
|
|
|
|
if !is_complete && error.is_none() {
|
|
error = Some(ParseError::ExtraTokens(Span::new(
|
|
curr_offset,
|
|
curr_offset + 1,
|
|
)));
|
|
}
|
|
let idx = curr_offset;
|
|
curr_offset += 1;
|
|
output.push(Token::new(
|
|
TokenContents::Semicolon,
|
|
Span::new(span_offset + idx, span_offset + idx + 1),
|
|
));
|
|
} else if c == b'\r' {
|
|
// Ignore a stand-alone carriage return
|
|
curr_offset += 1;
|
|
} else if c == b'\n' {
|
|
// If the next character is a newline, we're looking at an EOL (end of line) token.
|
|
let idx = curr_offset;
|
|
curr_offset += 1;
|
|
if !additional_whitespace.contains(&c) {
|
|
output.push(Token::new(
|
|
TokenContents::Eol,
|
|
Span::new(span_offset + idx, span_offset + idx + 1),
|
|
));
|
|
}
|
|
} else if c == b'#' {
|
|
// If the next character is `#`, we're at the beginning of a line
|
|
// comment. The comment continues until the next newline.
|
|
let mut start = curr_offset;
|
|
|
|
while let Some(input) = input.get(curr_offset) {
|
|
if *input == b'\n' {
|
|
if !skip_comment {
|
|
output.push(Token::new(
|
|
TokenContents::Comment,
|
|
Span::new(span_offset + start, span_offset + curr_offset),
|
|
));
|
|
}
|
|
start = curr_offset;
|
|
|
|
break;
|
|
} else {
|
|
curr_offset += 1;
|
|
}
|
|
}
|
|
if start != curr_offset && !skip_comment {
|
|
output.push(Token::new(
|
|
TokenContents::Comment,
|
|
Span::new(span_offset + start, span_offset + curr_offset),
|
|
));
|
|
}
|
|
} else if c == b' ' || c == b'\t' || additional_whitespace.contains(&c) {
|
|
// If the next character is non-newline whitespace, skip it.
|
|
curr_offset += 1;
|
|
} else {
|
|
let (token, err) = lex_item(
|
|
input,
|
|
&mut curr_offset,
|
|
span_offset,
|
|
additional_whitespace,
|
|
special_tokens,
|
|
in_signature,
|
|
);
|
|
if error.is_none() {
|
|
error = err;
|
|
}
|
|
is_complete = true;
|
|
output.push(token);
|
|
}
|
|
}
|
|
(output, error)
|
|
}
|
|
|
|
/// True if this the start of a redirection. Does not match `>>` or `>|` forms.
|
|
fn is_redirection(token: &[u8]) -> bool {
|
|
matches!(
|
|
token,
|
|
b"o>" | b"out>" | b"e>" | b"err>" | b"o+e>" | b"e+o>" | b"out+err>" | b"err+out>"
|
|
)
|
|
}
|